Safety razors



Oct. 16, 1956 E. JACOBSEN SAFETY RAZORS Filed Aug. 24, 1953 El III-E1 Alllr HII h lull" IF un,

I INVENTOR.

r 2,766,523 I Patented Oct. 16, 1956 SAFETY RAZORS Edwin Jacobsen,Altadena, Calif.

Application August 24, 1953, Serial No. 375,868

3 Claims. (Cl. 30-741) This invention relates to safety razors and wafertype blades wherein a substantially one piece razor is adapted to hold aperforated blade at a flat shaving attitude. The razor at the same timeexerting a tension in the blade intermediate of said perforations andthereby increasing substantially the natural frequency of the blade.

Since the apertures by which the blad is retained and stretched areparallel to and close to the cutting edges, the tensioning of the bladeoffers resistance to any rotation of the cutting edges about theretaining prongs of the razor.

In conventional safety razors the blade is more or less free to rotateabout the blade retention point, thus the distance between the safetyguard and the cutting edge often becomes larger or less than desired forsafety and good shaving. Further, since the natural frequency of aconventional wafer type blade is very low inherently, it follows thatthe amplitude due to the normal driving forces exerted upon it will behigh. This too, further aggravates the variation of distance between thecutting edges and th guard.

The above conditions are overcome in my present invention, by stressingthe blade in tension from 40,000 to 50,000 p. s. i., the naturalfrequency is increased many fold and the amplitude is decreasedproportionately.

In existing razors it is the practice to grip the blade on either sideof its flat surfaces in a manner to present its cutting edge in aproperly spaced relationship with the safety guard. In the case ofdouble edged blades, they are often curved and held adjacent to theguard members. In my invention the razor co-acts with the blade to holdthe blade in a flat plane in such a manner that it is free to vibrate.However the blade is held under tension or stretched so to speak, by apredetermined force varied by the movement of a handle slide. Thisvarying of the blade tension changes the rate at which the blade willvibrate when the cutting edge contacts an obstruction or severs a hair.

While a blade that is curved and under tension offers some very fineadvantages, it has been found that a blade held flat under tensionobviates the shear forces and blade cutting edge distortion due toantielastic bending obviously present in the curved blade. Further, theflat unbent blade held in the manner shown, resists the rotation of thecutting edge about the hooks by the tension in the intermediate portionof the blade interposed between th hooks.

The adjustment of the blade tension may be varied by moving the runneralong the handle of the razor. That is, the tension in the blade may beincreased or decreased by positioning the runner which exerts a constantpressure against the handles.

An object of the invention is to provide a one piece razor adapted tochange the natural frequency of a thin wafer type blade by preloading itin tension.

A further object of the invention is to provide a razor that willpositively grip and retain a razor blade in tension without the use ofscrew threads.

A further object of the invention is to provide a razor that will holdthe blade in a flat plane while under tens1on.

A furtherobject of the invention is to provide a razor that may berapidly rebladed and readily and easily cleaned.

With these and incidental objects in view, the invention consists incertain novel features of construction and combination of parts, apreferred form of which is hereinafter shown with reference to thedrawings which accompany and form a part of this specification.

In the drawings:

Fig. l is a top enlarged view of the assembled razor. F Fig. 2 is across sectional view taken on line 2--2,

Fig. 3 is a cross sectional view similar to Fig. 2, except that therunner is near the hinged end of the handle and the blade shown in aremoved position.

Fig. 4 is an enlarged plan view of the blade, removed to show theapertures in which the hooks engage.

Referring more particularly to the drawings, the upper handle 1, and thelower handle 2, are hinged together at one extreme end by the pin 3.These handles are channel shaped in cross section and form a box likechamber in which the runner 4, operates. This runner has the concavesurfaces 5 and 6, for thumb and finger grip when it is to be moved. Therollers 7, contact the inside surfaces 8, of the handles which areparallel for a major portion of the handle length. The springs 9, causethe rollers to exert a predetermined constant pressure against thesurfaces 8, for any position throughout the parallel length of thehandles.

The upper handle has the blade engagement hooks 10, and the lower handleblade engagement hooks 11, which are integrally formed with the handle.The cutting edge guard 12 and the edge rotector 13 are also integralwith th handles. The blade 14, has a multiplicity of apertures 15 whichthe hooks 10 and 11 engage.

By moving the runner 4 to the enlarged portion of the handle near thehinge pin 3, as shown in Fig. 3, the handle may be pressed togetherovercoming the tension of the spring 16. This action brings the hooks 10and 11 closer together. As the runner 4 is moved to any position in theparallel portion of the handle as shown in Fig. 3, it is obvious that wenow have two simply supported beams with a load, represented by thesprings y, acting equally and oppositely between them. It can be shownthat by moving the load, the runner 4, along the handles that the loadon the hinge pin 3, will increase if the runner is moved in thedirection of the pin. It also follows that in this case the load on theblade 14 will, decrease. Moving the runner toward the blade as shown. inFig. 2 will decrease the load on the pin 3, and increasev the tensionload on the blade 14.

blade to meet various conditions.

While the form of mechanism herein shown and tie-- scribed is admirablyadapted to fulfill the objects primarily stated, it is to be understoodthat it is not intended to confine the invention to the form ofembodiment herein shown and described as it is susceptible of em--bodiment in various forms all coming within the scope: of the claimswhich follow.

What I claim is:

1. In a combination with a wafer type perforated blade, a razorconsisting of a pair of handle elements hinged together near one extremeend, blade engagement hooks disposed near the other extreme end of thehandle elements, said handle elements being substantially symmetricalchannel shaped members normally parallel to In this manner, with. aconstant load against the handles, it is possible tov modulate the loadand consequently the p. s. i. loading on. the blade, thus it is possibleto vary the frequency of the.

each other through the major portion of their length when said hooksengage with the blade, said one end of the handle elements sloping so asto produce opposing angles to the normal parallel portion of said handleelements, a spring loaded runner having finger grips slidably disposedin the channels between said handle elements and adapted to exert aconstant predetermined outward pressure on the parallel surfaces of thehandle elements, said runner constituting means for varying the tensionloading on the engaged blade.

2. In combination with a flat wafer type blade adapted to be held inpredetermined tension, a razor consisting in an integral guard and lowerhandle element, blade engagement elements integrally formed from saidguard clement, an upper handle element with integral blade attachmentelements at its outer end, said upper and lower handle elements hingednear the extreme end in such a manner that when the blade is on theattachment elements said handles are substantially parallel, a preloadedrunner slidably disposed between the handle ele- 30 ments for securingthe blade to the razor by forcing the handle elements apart andconstituting means for varying the tension exerted on the blade bymovement of the runner.

3. In combination with a wafer type thin double edged blade, a razorconsisting of an upper handle element, a lower handle element and aspring loaded runner, said handle elements having channel shapedportions hinged together near one end, the other ends terminating in theblade engagement and guard elements, said channel shaped portionproviding parallel surfaces when said blade is in place, said runnerslidably disposed within the channel shaped portions of the handles,exerting a constant outward pressure along the parallel surfaces whenthe blade is in place, said parallel surfaces angling outwardly from therunner near the hinge end of the handles, providing an area in which therunner may be placed when installing and removing the blade.

References Cited in the file of this patent UNITED STATES PATENTS851,341 Bullard Apr. 23, 1907 1,111,721 Gillette Sept. 22, 19141,984,243 Wharton Dec. 11, 1934 FOREIGN PATENTS 416,014 France July 27,1910

